If the diagram shows lift but doesn't show the air being directed downward after leaving the tailing edge of the wing, I basically stop reading. That's the whole thing.
Thank. You. That's exactly what is missing and that's exactly what I have mentioned in my... highly criticised comment. It just shows how pervasive the misconception is.
If you take a step back there is a simple way to think about this. In order for the object to stay up there, there needs to be equal and opposite force from some other body. What is that other body? It is the mass of air that is being directed in the opposite direction of the lift force acting on the plane.
I think the mistake this site is making is trying to model out pressure changes that would create an airfoil-like shape of airflow. That's not how wings work. The pressure at the wing's leading surface is infinite because there's a metal skin there. You don't need a low pressure zone sucking air up 1m above it to explain that.
This view also implies that most of the lift is happening on the very front edge of the wing which I doubt is accurate otherwise we would have very skinny wings.
Unfortunately it partly bitrotted due to using java applets for interactive demos, but I think most of it is still reachable - I'll try to find it later when I'm at the desk.
Personally I learnt from a 1980 book that was still part of mandatory reading for glider pilot course in Poland in 2005.
